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simd_shift_by_immediate: Simplify ShiftRight

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This commit is contained in:
MerryMage 2018-07-24 16:38:51 +01:00
parent f020dbe4ed
commit c5722ec963
1 changed files with 36 additions and 58 deletions
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94
src/frontend/A64/translate/impl/simd_shift_by_immediate.cpp
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@ -9,19 +9,23 @@
namespace Dynarmic::A64 {
namespace {
enum class ShiftExtraBehavior {
enum class Rounding {
None,
Accumulate,
Round
};
enum class Accumulating {
None,
Accumulate
};
enum class Signedness {
Signed,
Unsigned
};
bool ShiftRight(TranslatorVisitor& v, bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd,
ShiftExtraBehavior behavior, Signedness signedness) {
Rounding rounding, Accumulating accumulating, Signedness signedness) {
if (immh == 0b0000) {
return v.DecodeError();
}
@ -34,8 +38,10 @@ bool ShiftRight(TranslatorVisitor& v, bool Q, Imm<4> immh, Imm<3> immb, Vec Vn,
const size_t datasize = Q ? 128 : 64;
const u8 shift_amount = static_cast<u8>(2 * esize) - concatenate(immh, immb).ZeroExtend<u8>();
const u64 round_value = 1ULL << (shift_amount - 1);
const IR::U128 operand = v.V(datasize, Vn);
IR::U128 result = [&] {
if (signedness == Signedness::Signed) {
return v.ir.VectorArithmeticShiftRight(esize, operand, shift_amount);
@ -43,7 +49,13 @@ bool ShiftRight(TranslatorVisitor& v, bool Q, Imm<4> immh, Imm<3> immb, Vec Vn,
return v.ir.VectorLogicalShiftRight(esize, operand, shift_amount);
}();
if (behavior == ShiftExtraBehavior::Accumulate) {
if (rounding == Rounding::Round) {
const IR::U128 round_const = v.ir.VectorBroadcast(esize, v.I(esize, round_value));
const IR::U128 round_correction = v.ir.VectorEqual(esize, v.ir.VectorAnd(operand, round_const), round_const);
result = v.ir.VectorSub(esize, result, round_correction);
}
if (accumulating == Accumulating::Accumulate) {
const IR::U128 accumulator = v.V(datasize, Vd);
result = v.ir.VectorAdd(esize, result, accumulator);
}
@ -52,44 +64,8 @@ bool ShiftRight(TranslatorVisitor& v, bool Q, Imm<4> immh, Imm<3> immb, Vec Vn,
return true;
}
bool RoundingShiftRight(TranslatorVisitor& v, bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd,
ShiftExtraBehavior behavior, Signedness signedness) {
if (immh == 0b0000) {
return v.DecodeError();
}
if (!Q && immh.Bit<3>()) {
return v.ReservedValue();
}
const size_t datasize = Q ? 128 : 64;
const size_t esize = 8 << Common::HighestSetBit(immh.ZeroExtend());
const u8 shift_amount = static_cast<u8>((esize * 2) - concatenate(immh, immb).ZeroExtend());
const u64 round_value = 1ULL << (shift_amount - 1);
const IR::U128 operand = v.V(datasize, Vn);
const IR::U128 round_const = v.ir.VectorBroadcast(esize, v.I(esize, round_value));
const IR::U128 round_correction = v.ir.VectorEqual(esize, v.ir.VectorAnd(operand, round_const), round_const);
const IR::U128 result = [&] {
if (signedness == Signedness::Signed) {
return v.ir.VectorArithmeticShiftRight(esize, operand, shift_amount);
}
return v.ir.VectorLogicalShiftRight(esize, operand, shift_amount);
}();
IR::U128 corrected_result = v.ir.VectorSub(esize, result, round_correction);
if (behavior == ShiftExtraBehavior::Accumulate) {
const IR::U128 accumulator = v.V(datasize, Vd);
corrected_result = v.ir.VectorAdd(esize, accumulator, corrected_result);
}
v.V(datasize, Vd, corrected_result);
return true;
}
bool ShiftRightNarrowing(TranslatorVisitor& v, bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd,
ShiftExtraBehavior behavior) {
Rounding rounding) {
if (immh == 0b0000) {
return v.DecodeError();
}
@ -103,17 +79,19 @@ bool ShiftRightNarrowing(TranslatorVisitor& v, bool Q, Imm<4> immh, Imm<3> immb,
const size_t part = Q ? 1 : 0;
const u8 shift_amount = static_cast<u8>(source_esize - concatenate(immh, immb).ZeroExtend());
const u64 round_value = 1ULL << (shift_amount - 1);
IR::U128 operand = v.ir.GetQ(Vn);
const IR::U128 operand = v.V(128, Vn);
if (behavior == ShiftExtraBehavior::Round) {
const u64 round_const = 1ULL << (shift_amount - 1);
const IR::U128 round_operand = v.ir.VectorBroadcast(source_esize, v.I(source_esize, round_const));
operand = v.ir.VectorAdd(source_esize, operand, round_operand);
IR::U128 wide_result = v.ir.VectorLogicalShiftRight(source_esize, operand, shift_amount);
if (rounding == Rounding::Round) {
const IR::U128 round_const = v.ir.VectorBroadcast(esize, v.I(esize, round_value));
const IR::U128 round_correction = v.ir.VectorEqual(esize, v.ir.VectorAnd(operand, round_const), round_const);
wide_result = v.ir.VectorSub(esize, wide_result, round_correction);
}
const IR::U128 result = v.ir.VectorNarrow(source_esize,
v.ir.VectorLogicalShiftRight(source_esize, operand, shift_amount));
const IR::U128 result = v.ir.VectorNarrow(source_esize, wide_result);
v.Vpart(64, Vd, part, result);
return true;
@ -150,19 +128,19 @@ bool ShiftLeftLong(TranslatorVisitor& v, bool Q, Imm<4> immh, Imm<3> immb, Vec V
} // Anonymous namespace
bool TranslatorVisitor::SSHR_2(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd) {
return ShiftRight(*this, Q, immh, immb, Vn, Vd, ShiftExtraBehavior::None, Signedness::Signed);
return ShiftRight(*this, Q, immh, immb, Vn, Vd, Rounding::None, Accumulating::None, Signedness::Signed);
}
bool TranslatorVisitor::SRSHR_2(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd) {
return RoundingShiftRight(*this, Q, immh, immb, Vn, Vd, ShiftExtraBehavior::None, Signedness::Signed);
return ShiftRight(*this, Q, immh, immb, Vn, Vd, Rounding::Round, Accumulating::None, Signedness::Signed);
}
bool TranslatorVisitor::SRSRA_2(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd) {
return RoundingShiftRight(*this, Q, immh, immb, Vn, Vd, ShiftExtraBehavior::Accumulate, Signedness::Signed);
return ShiftRight(*this, Q, immh, immb, Vn, Vd, Rounding::Round, Accumulating::Accumulate, Signedness::Signed);
}
bool TranslatorVisitor::SSRA_2(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd) {
return ShiftRight(*this, Q, immh, immb, Vn, Vd, ShiftExtraBehavior::Accumulate, Signedness::Signed);
return ShiftRight(*this, Q, immh, immb, Vn, Vd, Rounding::None, Accumulating::Accumulate, Signedness::Signed);
}
bool TranslatorVisitor::SHL_2(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd) {
@ -185,11 +163,11 @@ bool TranslatorVisitor::SHL_2(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd)
}
bool TranslatorVisitor::SHRN(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd) {
return ShiftRightNarrowing(*this, Q, immh, immb, Vn, Vd, ShiftExtraBehavior::None);
return ShiftRightNarrowing(*this, Q, immh, immb, Vn, Vd, Rounding::None);
}
bool TranslatorVisitor::RSHRN(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd) {
return ShiftRightNarrowing(*this, Q, immh, immb, Vn, Vd, ShiftExtraBehavior::Round);
return ShiftRightNarrowing(*this, Q, immh, immb, Vn, Vd, Rounding::Round);
}
bool TranslatorVisitor::SSHLL(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd) {
@ -197,19 +175,19 @@ bool TranslatorVisitor::SSHLL(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd)
}
bool TranslatorVisitor::URSHR_2(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd) {
return RoundingShiftRight(*this, Q, immh, immb, Vn, Vd, ShiftExtraBehavior::None, Signedness::Unsigned);
return ShiftRight(*this, Q, immh, immb, Vn, Vd, Rounding::Round, Accumulating::None, Signedness::Unsigned);
}
bool TranslatorVisitor::URSRA_2(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd) {
return RoundingShiftRight(*this, Q, immh, immb, Vn, Vd, ShiftExtraBehavior::Accumulate, Signedness::Unsigned);
return ShiftRight(*this, Q, immh, immb, Vn, Vd, Rounding::Round, Accumulating::Accumulate, Signedness::Unsigned);
}
bool TranslatorVisitor::USHR_2(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd) {
return ShiftRight(*this, Q, immh, immb, Vn, Vd, ShiftExtraBehavior::None, Signedness::Unsigned);
return ShiftRight(*this, Q, immh, immb, Vn, Vd, Rounding::None, Accumulating::None, Signedness::Unsigned);
}
bool TranslatorVisitor::USRA_2(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd) {
return ShiftRight(*this, Q, immh, immb, Vn, Vd, ShiftExtraBehavior::Accumulate, Signedness::Unsigned);
return ShiftRight(*this, Q, immh, immb, Vn, Vd, Rounding::None, Accumulating::Accumulate, Signedness::Unsigned);
}
bool TranslatorVisitor::USHLL(bool Q, Imm<4> immh, Imm<3> immb, Vec Vn, Vec Vd) {